Thread: Problem with writing commands to GP-635T

Hi everyone,

I am working on my senior design project at the University of Florida and part of our project involves using a GPS module. I am using the GP-635T, the link to the data sheet is below.

This chip, relatively cheap, outputs standard NMEA messages at a rate of 1Hz and claims to be able to output messages up to 5 Hz. Here is where my question lies. I am using a terminal program to communicate with the chip called RealTerm:Serial/TCP Terminal, I also posted a link to their website below if you want to look into that.

I am trying to send commands to the chip to disable all the NMEA message I do not need and increase the rate up to 5Hz. So far nothing is working. I have found Query/Rate control commands and a few PDF's that look helpful, but I still cannot change the output of the chip.

My setup: I have a usb cable connected to a FTDI232 and a GP-635T with all the proper connections. Tx(gps)>Rx(ftdi) and Tx(ftdi)>Rx(gps). I know they are communicating because I can read the data coming from the GPS to the terminal screen, but when I try to write the commands to the gps I get the error message

$GPTXT,01,01,01,PSRF inv format*2B<CR><LF>

I am sending the code "$PSRF103,05,00,00,01*21" without the quotations with the <CR><LF> EOL through the terminal program and I am extremely confused because this is EXACTLY what the guides/manuals say.

Any help is greatly appreciated. I will be out of town for a week or so after tomorrow, so if I don't respond immediately that is the reason. I will also post this in the general forum, sorry if this thread is misplaced.

Thank you again,
Alex


Datasheet: [Only registered and activated users can see links. ]
Terminal Program I'm using: [Only registered and activated users can see links. ]